Solar Wind and its Evolution

TL;DR

This paper uses magnetohydrodynamical simulations to explore how the solar wind's properties and behavior have evolved over time, focusing on the influence of magnetic flux tube parameters and forces.

Contribution

It introduces a simulation approach to model past solar wind conditions by varying key parameters, providing insights into historical solar wind density and speed differences.

Findings

Past solar wind was denser and slightly slower without significant magneto-centrifugal effects.

Magneto-centrifugal force influences solar wind acceleration and density.

Coronal mass ejections also play a role in solar wind dynamics.

Abstract

By using our previous results of magnetohydrodynamical simulations for the solar wind from open flux tubes, I discuss how the solar wind in the past is different from the current solar wind. The simulations are performed in fixed one-dimensional super-radially open magnetic flux tubes by inputing various types of fluctuations from the photosphere, which automatically determines solar wind properties in a forward manner. The three important parameters which determine physical properties of the solar wind are surface fluctuation, magnetic field strengths, and the configuration of magnetic flux tubes. Adjusting these parameters to the sun at earlier times in a qualitative sense, I infer that the quasi-steady-state component of the solar wind in the past was denser and slightly slower if the effect of the magneto-centrifugal force is not significant. I also discuss effects of magneto-centrifugal force and roles of coronal mass ejections.